An improved image processing method for particle characterization by shadowgraphy

[EN] Shadowgraphy is one of the most popular imaging techniques to characterize moving particles by their size, geometry as well as velocity, due to its simplicity. However, it requires advanced image processing to handle various image defects such as non-uniform illumination, overlapped particles, etc., which are normally only solved for individual applications. This study proposes a robust image processing method for particle shadowgraphy, aiming to process imperfect particle shadow images. The proposed method first detects qualified particles from particle shadow images, and then processes detected particles individually. Therefore different defects from different particles can be handled separately and locally. An overlapped particles detection and separation algorithm is also implemented to improve the accuracy of size and geometry characterization. The proposed method is first proved by synthetic generated particle shadow images, followed by a proof test with shadow images from a transparent dot pattern target. Finally this method is successfully applied to a shadow image acquired from a water spray and proved to be able to handle various issues of shadowgraphy.This work is supported by a collaboration project among IRSTEA, IRPHE and Dantec Dynamics A/S, aiming to improve characterization of moving irregular particles by shadowgraphy measurements.Wang, H.; Felis, F.; Tomas, S.; Anselmet, F.; Amielh, M. (2017). An improved image processing method for particle characterization by shadowgraphy. En Ilass Europe. 28th european conference on Liquid Atomization and Spray Systems. Editorial Universitat Politècnica de València. 962-967. https://doi.org/10.4995/ILASS2017.2017.4614OCS96296

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Anxiety in women referred for colposcopy: a prospective observational study

Purpose!#!To evaluate the occurrence of anxiety in women attending a colposcopic examination within the new cervical cancer screening in Germany.!##!Methods!#!One hundred and fifty-six patients were asked to fill out Spielbergers STAI inventory form prior to their colposcopic examination. For the statistical analysis, a two by two between-group design was applied including the following group factors: the repeat factors included patients, who presented to our centre of dysplasia for the first time (new) and patients who have had an examination in our centre before (repeat). Further, the factor diagnosis included two groups: first, patients with cervical dysplasia and second, patients with vulva diseases.!##!Results!#!The analysis of the STAI results showed that patients presenting with cervical dysplasia for the first time had the highest levels of anxiety, directly followed by new patients in the vulva group. The ANOVA revealed a main effect of the repeat factor, F(1,140) = 7.53, p = 0.007. There was no significant effect of diagnosis.!##!Conclusion!#!Regardless of the diagnosis, patients being transferred for a colposcopy within the cervical cancer screening program for the first time have very high anxiety levels. The prospect of a potentially painful examination seems to be a key factor. Only a scientific evaluation of the new cervical cancer screening will be able to show if the rising numbers of colposcopic examinations is really worth the risk of exposing so many more women to the emotional distress of a colposcopy

Experiments to quantity aerosol transport from sprinkler irrigation and to assess in field sampling methods

International audienc

Experiments to quantity aerosol transport from sprinkler irrigation and to assess in field sampling methods

International audienc

Stereoscopic MicroPIV Measurements in A Labyrinth-Channel Dripper Used in Micro-Irrigation Systems

International audienceSmall serpentine-shaped channels used in drip irrigation is an efficient irrigation technique in order to spare water. Eventual clogging in such micro channels should be avoided to extend the lifetime of these irrigation systems. Clogging often occurs when sedimentation takes place in low or zero velocity regions in steady laminar flow conditions. For this reason, labyrinth dripper designs are used to enhance mixing and / or induce unsteady flow conditions inside the channel. The aim of the present study is to investigate the flow inside such millimetric complex channel geometry with Stereoscopic MicroPIV measurements. Current three-component (3C) velocity measurements are compared with previous two-component (2C) velocity measurements. Results indicate that the u and v components of the 3C measurements are in good agreement with the previous 2C measurements, identifying and confirming the previously measured low- and zero-velocity regions. Furthermore, the out-of-plane (w) velocity component adds new information about the flow field revealing three-dimensional (3D) flow structures, what appears to be oblique vortices emanating from the baffle tips. In conclusion, both enhanced mixing due to 3D vortices and induced unsteady flow field seems to be responsible for clogging suppression

Stereoscopic MicroPIV Measurements in A Labyrinth-Channel Dripper Used in Micro-Irrigation Systems

International audienceSmall serpentine-shaped channels used in drip irrigation is an efficient irrigation technique in order to spare water. Eventual clogging in such micro channels should be avoided to extend the lifetime of these irrigation systems. Clogging often occurs when sedimentation takes place in low or zero velocity regions in steady laminar flow conditions. For this reason, labyrinth dripper designs are used to enhance mixing and / or induce unsteady flow conditions inside the channel. The aim of the present study is to investigate the flow inside such millimetric complex channel geometry with Stereoscopic MicroPIV measurements. Current three-component (3C) velocity measurements are compared with previous two-component (2C) velocity measurements. Results indicate that the u and v components of the 3C measurements are in good agreement with the previous 2C measurements, identifying and confirming the previously measured low- and zero-velocity regions. Furthermore, the out-of-plane (w) velocity component adds new information about the flow field revealing three-dimensional (3D) flow structures, what appears to be oblique vortices emanating from the baffle tips. In conclusion, both enhanced mixing due to 3D vortices and induced unsteady flow field seems to be responsible for clogging suppression

Stereoscopic MicroPIV Measurements in A Labyrinth-Channel Dripper Used in Micro-Irrigation Systems

International audienceSmall serpentine-shaped channels used in drip irrigation is an efficient irrigation technique in order to spare water. Eventual clogging in such micro channels should be avoided to extend the lifetime of these irrigation systems. Clogging often occurs when sedimentation takes place in low or zero velocity regions in steady laminar flow conditions. For this reason, labyrinth dripper designs are used to enhance mixing and / or induce unsteady flow conditions inside the channel. The aim of the present study is to investigate the flow inside such millimetric complex channel geometry with Stereoscopic MicroPIV measurements. Current three-component (3C) velocity measurements are compared with previous two-component (2C) velocity measurements. Results indicate that the u and v components of the 3C measurements are in good agreement with the previous 2C measurements, identifying and confirming the previously measured low- and zero-velocity regions. Furthermore, the out-of-plane (w) velocity component adds new information about the flow field revealing three-dimensional (3D) flow structures, what appears to be oblique vortices emanating from the baffle tips. In conclusion, both enhanced mixing due to 3D vortices and induced unsteady flow field seems to be responsible for clogging suppression